A colorful account of the studies man has made in his attempt to discover the fundamental characteristics of living matter

F ROM THE EARLIEST times i t has been believed that living things can originate spontaneously from non-living material. For centuries it was thought, for example, that worms, frogs, insects and scorpions could originate in mud, or from dew or decaying meat, without parents. Known as the doctrine of spontaneous generation, this was the view of the classical Greek authors Aristotle, Lucretius and others who influenced Western thinking for 2,000 years. It was the generally accepted view all through the Middle Ages and well into the 17th century. The following quotation from the works of a wellknown physician and chemist named Van Helmont, who lived from 1577 to 1644, is typical: